Laser cutting is a non-traditional processing method that uses an intensely focused stream of coherent light called a laser to cut material. It is a subtractive process in which the material is continuously removed during the cutting process. This is accomplished by vaporization, melting, chemical ablation, or controlled crack propagation.
The laser optics are digitally controlled by CNC (Computer Numerical Control), making the process suitable for drilling holes as small as 5 microns. In addition, the process does not create residual stresses in the material, allowing the cutting of delicate and fragile materials.
How Do Laser Cutting Work?
A laser cutting machine works similarly to a CNC machine, but it uses a high-power laser. The laser will guide the material or beam through the CNC and optical equipment. The machine will use the CNC, or G-code provided, to cut the material and control the motion.
After the laser beam is focused, the material will melt, vaporize and burn. In addition, when you blow the material with a gas jet, you can obtain a high-quality finished edge surface. The laser beam generation takes place in a closed container, where a lamp or electrical discharge stimulates the luminescent material.
The amplification of the luminescent material occurs after internal reflection through a partial mirror. This phenomenon continues until enough energy has accumulated in a coherent monochromatic light stream to allow it to escape. The intensity of the light increases after it has been focused on the working area using a fiber or mirror.
The laser beam diameter is below 0.32 mm at its thinnest edge. Conversely, the width of the incision can potentially be as small as 0.10 mm. However, this depends on the thickness of the material. If the material is cut with a laser cutter without starting from the edge of the material, then a perforation process is used.
Types Of Laser Cutting
For cutting, there are three primary types of lasers. They are CO2, Nd-YAG (neodymium yttrium aluminum garnet), and fiber lasers. They differ in the base material used to generate the laser beam.
Carbon dioxide lasers
This type of laser has a gas discharge medium filled with 10-20% carbon dioxide, 10-20% nitrogen, trace amounts of hydrogen and xenon, and helium. Laser pumping is done not by light but by discharge current.
As the discharge passes through the illumination medium, the nitrogen molecules are excited to a higher energy level. Unlike previously described, these excited nitrogen molecules do not lose energy due to photon emission.
Instead, it transfers the energy of its vibrational modes to the CO2 molecules. This process continues until most CO2 molecules are in a transferable state. The carbon dioxide molecules then emit infrared light at 10.6 µm or 9.6 µm, bringing them to a lower energy level.
Resonant mirrors are designed to reflect the emitted photons at these wavelengths. A mirror is a partial reflector that allows the release of the infrared beam used to cut the material.
After releasing the infrared light, the CO2 molecule returns to the ground state by transferring its remaining energy to the doped helium atoms. The cold helium atoms then become very hot and are cooled by the laser’s cooling system. CO2 lasers have an efficiency of about 30%, higher than other lasers.
Crystal (ruby, Nd and Nd-YAG) lasers
Unlike CO2 lasers, this type of laser is a solid-state laser that uses synthetic crystals as the light-emitting medium. The most common is a YAG (Y3Al5O12) crystal doped with 1% ionized neodymium (Nd3+).
The Nd ions in this crystal replace the Y ions in the crystal structure. The rods are approximately 10 cm in length and 6 to 9 cm in diameter. The ends of the YAG rods are polished and coated with a highly reflective material that serves as a resonator system.
A krypton flash or laser diode achieves laser pumping. This laser pumping excites neodymium ions to higher energy levels. After some time, the excited neodymium ions enter a lower, more stable state without emitting photons. This process continues until the medium is filled with excited Nd ions. From its degraded state, the Nd ion emits infrared light at a wavelength of 1064 nm.
Fiber lasers
Fiber lasers are a newer form of laser that emits light using optical fibers rather than gases (CO2 lasers) or crystals (Nd-YAG lasers). Because it uses optical fibers, fiber lasers are solid-state lasers that work similarly to crystal lasers.
The optical fiber is doped with elements such as erbium and ytterbium. Erbium produces light in the range of 1528 to 1620 nm. On the other hand, ytterbium produces light at 1030 nm, 1064 nm, and 1080 nm.
It is known that when light passes through an optical fiber, it stays inside with minimal energy loss. This makes optical fibers more stable than other types requiring accurate alignment.
Advantages Of Laser Cutting Machine
High Precision and Accuracy
Lasers employ a focused beam of light to cut objects with extreme precision. The laser is powerful and tiny, but it melts and evaporates material with unrivaled precision. Most of the time, laser tolerances range from 0.003 mm to 0.006 mm.
Plasma cutters have a tolerance level of about 0.02 mm, which is higher than laser cutting. Similarly, other cutting tools have tolerance levels between 1 and 3 mm, or even higher. Suppose that a high precision and accuracy machine is required in the manufacturing process.
In this case, the preferred tool is usually a laser cutter. Therefore, the aerospace industry uses laser cutting, which requires tight tolerance levels.
Lower cost and more affordable
Laser cutting has an economic advantage over other CNC machines of the same caliber, which is one of the advantages of laser technology. Custom tools are no longer necessary, thanks to laser cutting technology. You also don’t need to modify the equipment for any project because no additional cutting tools are needed.
In addition, there is no physical contact, so there is no wear and tear on the surface. Because laser cutting machines have few mechanical parts, they are less expensive to maintain than other processing technologies. The machine’s running cost will also be lower compared to traditional manufacturing tools.
For jobs of extreme complexity
Many tasks that may be too complex for other cutting technologies will become simple for laser cutting machines; laser technology can work on the thinnest edges of the material. Although the cut area may be slightly distorted or twisted, you can produce complex geometries quickly with a laser cutter. Laser cutting has a wide tolerance level and can accommodate various materials.
High sheet utilization and less waste
When you cut material with a laser cutter, only a very small amount of material is wasted. This makes laser cutting stand out from other machines with a significant portion of material. With a laser cutter, manufacturers can maximize the use of material. As resources are utilized more efficiently, less material is wasted, and production costs are reduced.
Damage prevention
Another benefit of laser cutting is avoiding damage, even to the narrowest of materials. Many people tend to believe misinformation about the machine, believing that distortion or damage to the material is inevitable.
This popular belief premise that high heat is used in the laser cutting process. You should note that heat affects only a small material area and does not affect tolerances. Laser cutting of sheets is amazingly fast, so the time required for cutting is less. As a result, manufacturers can easily avoid warping and distortion.
Low power consumption
It would help if you had a lot of power to achieve a cut in real life. However, laser-cutting machines do not have any other moving parts, which reduces energy consumption. In contrast, machines with movable parts tend to consume more energy. In addition, laser cutters cut material in a very fast time. This helps save time and power. When less energy is consumed, the cost of operation is also reduced.
Disadvantages Of Laser Cutting Machine
While laser cutting has many benefits, it also has some drawbacks that you should be aware of. We will discuss some of them below.
Laser cutting of plastics produces toxic fumes and requires ventilation, which can be an expensive task.
Effective laser cutting also depends on the thickness of the part, the material being cut, and the type of laser being used. Without proper care, the cut material can be burned, and some metals can discolor unless the correct laser intensity is used. While plasma cutting can still cut thicker sheets than laser cutting, advances in laser technology mean this gap is closing, although machine costs are still high.
Finally, although it is an automated process, commissioning and maintenance require human involvement, and there is a risk of serious burns if the operator comes into contact with the laser.
Application Of Laser Cutting
As previously stated, laser cutting is an exciting sector that is always evolving.
Here are some of the most prevalent laser-cutting uses nowadays.
Automotive Industry
Laser cutting has found a home in the automotive industry due to its ability to reproduce parts with relative speed and accuracy. Accurate reproduction of parts of various forms and sizes is critical in the automotive sector. Laser cutting is used to cut metals and plastics to form body parts, electronic components, interior covers, and buttons for automobiles.
In addition, laser-cutting machines can engrave buttons on automotive interiors to allow light to shine through and record serial and part numbers on manufactured parts. Molds used to cut different parts can also be cut with a laser.
Laser cutting is suitable for cutting hydroformed parts. These are typically sturdy tubes that offer support for the vehicle’s construction. Typically, these parts are used to create engine frames or instrument panels.
Mold and tooling industry
As previously noted, laser cutting can be utilized to make molds for duplicate parts. Using the laser’s ability to cut different depths in metal, extremely accurate molds can be created for stamped parts that can be used consistently through a repetitive die-cutting process.
Duplicating molds with laser cutting is also a quick and accurate process.
Injection molds can be made with the same precision as molds using laser cutting.
This simplifies the mold-making process and makes accurate mold reproduction a much faster and more expensive procedure.
In tool manufacturing, laser cutters can be used for marking and engraving in the automotive industry and for making simple hand tools. The speed of laser cutters may even make them better than die-cutting on strong metals. Because of the versatility of its material uses, you can even laser engrave company logos and tool information on the rubber handles of most tools.
Jewellery industry
The precision of laser cutting makes it easy to use in jewelry making processes. For example, imagine a watch with many small gears. Lasers are cut with precision to make gears with less waste and production time. In addition, the laser’s engraving capabilities allow parts to be marked during the manufacturing process.
Because lasers can cut precise shapes and thicknesses, laser cutting can also be used to make jewelry. Creating a ring or bracelet of precise width, depth and diameter can be easily accomplished with a laser. Lasers can also engrave designs and inscriptions on interior or exterior surfaces.
Medical Device Manufacturing
The most significant advantages of laser cutting in the medical industry are laser surgery and the fabrication of medical products.
Laser surgery allows surgeons to make precise cuts, and patients heal faster. Laser-cut parts are used to manufacture medical devices that improve the quality of life for patients. For example, stents, valve frames, vascular clips, bone hinges, flexible shafts, and reamers are all made from laser-cut parts.
Ceramic Manufacturing
Ceramics have various qualities that enable engineers to employ them in various applications. Their low electrical and thermal conductivity make them excellent insulators. They do not react with other chemicals, have a high melting point, and are extremely durable.
Lasers are often used to cut ceramics because they reduce processing time without sacrificing edge quality. Aircraft jet engines, electric motors, speakers, headphones, power plant generators, rice cookers, and even incandescent lamps have ceramic parts.
Silicon Manufacturing
Another material that can benefit from laser cutting is silicon, which has many applications. Precision cutting allows engineers to produce smaller silicon parts than those made using other cutting methods.
Silicon is resistant to high temperatures and aging, and it is easy to work with. Typical applications for silicon are found in computers, electronics, textiles, household products, automobiles, and construction.
Conclusion
The introduction of laser cutting has provided valuable benefits to the manufacturing industry. The machine helps to cut many materials in one period, thus saving time and reducing operating costs. Understanding the pros and cons of laser cutting will help you make the best choice for your project.